(CNN) -- Jewish organizations called for a Romanian official to resign and face a criminal investigation after he wore a Nazi uniform during a fashion show over the weekend.

Radu Mazare, the mayor of the town of Constanta, wore a Nazi uniform during a fashion show over the weekend.

Radu Mazare, the mayor of the town of Constanta, and his 15-year-old son "entered the stage marching the clearly identifiable Nazi 'goose step,'" the Center for Monitoring and Combating anti-Semitism in Romania said in a letter to the country's prosecutor general.

The organization's director, Marco Katz, said Mazare had broken Romanian law and encouraged his son to do the same, "educating him to treat the law with contempt."

Katz said Mazare was sending a message "that to wear Nazi uniforms and to march the Nazi steps is legal and 'in vogue' in Romania."

He urged the authorities and the head of Mazare's Social Democrat party to show that message "will be strongly countermanded."

Mazare, 41, said he had not noticed the Nazi swastika symbol on the uniform before he wore it, according to the Romanian Times newspaper.

"I checked it before I put it on but the swastika was very small and I didn't see it," he said. "I really liked the look of the uniform after seeing it in the Tom Cruise film 'Valkyrie.' I bought it from a costume hire shop in Germany."

A top Nazi hunter said Mazare should quit.

"The proper thing for you to do is to admit your mistake, apologize for it and resign your position," Efraim Zuroff of the Simon Wiesenthal Center in Jerusalem wrote to Mazare. Zuroff sent CNN a copy of the letter.

He said it was no defense that the uniform was that of the Wehrmacht -- the army -- rather than the SS, the elite Nazi guard which took the lead in killing Jews during the Holocaust.

"The Wehrmacht played an active role in the mass murder of European Jewry and many other innocent victims. By dressing in a Wehrmacht uniform, you are expressing totally unwarranted support and nostalgia for an army which committed the most terrible war crimes and acts of genocide," the letter said.

"It would hard to adequately describe the depth of the pain that your appearance caused, not only to Jews and other victims of Nazism, but to any person of moral integrity who knows the history of World War II," Zuroff wrote.

Zuroff told CNN he did not expect Mazare to resign, or even to respond to the letter.

But he said he hoped the mayor might act on Zuroff's suggestion that Mazare create a Romanian-language edition of an acclaimed exhibition on the crimes of the Wehrmacht.

The Nazi uniform incident, which took place Sunday, was the first time Zuroff heard of Mazare, he said.

"He has a history of being outrageous, but his antics have never included something that I would deal with," Zuroff said.

"He's a real character, apparently. He's also very popular, which makes this much more difficult."

CNN attempts to contact Mazare were unsuccessful.

Romania was a Nazi ally from 1940 to 1944, under the leadership of a right-wing military government led by General Ion Antonescu.

At least 270,000 Romanian Jews were killed or died from mistreatment during the Holocaust, according to the Holocaust Encyclopedia.

The 1930 Romanian census recorded 728,115 people who identified themselves as Jewish, comprising approximately 4 percent of the population, the reference work says.

Antonescu was deposed in 1944 and Romania switched sides in World War II.